As a technique regarding a heat dissipation design for a radio frequency transmitting and receiving power semiconductor device mounted on a mobile information terminal such as a mobile phone, a mounting structure for reducing the heat resistance is disclosed, for example, in Japanese Patent Application Laid-Open Publication No. 2001-102483 (Patent Document 1) and Japanese Patent Application Laid-Open Publication No. 2004-71597 (Patent Document 2). From among these documents, the mounting structure disclosed in the Patent Document 1, as shown in the sectional view shown in FIG. 1 has a face-up structure in which a circuit forming region (active region) of a semiconductor element 1 is located on an element, and moreover, adapts a system in which a heat conducting member which is a connecting member is used between the element bottom and a wiring substrate, and this heat conducting member functions as a so-called heat diffusion plate.
On the other hand, the mounting structure disclosed in the Patent Document 2, similarly to the sectional view shown in FIG. 2, is a structure in which a plurality of semiconductor elements are laminated on the wiring substrate by a face down system that directs the active region to the element bottom side, that is, a flip-chip connecting system. In this case, a system is adapted such that a power semiconductor element large in heat value is disposed on the lowest part of the power semiconductor device, and radiates heat directly to the wiring substrate by a bump structure of a large area exclusive for heat dissipation.
One example of the structure that improves heat dissipation of the semiconductor elements laminated in a stacked state is disclosed in Japanese Patent Application Laid-Open Publication No. 2000-31309 (Patent Document 3) and Japanese Patent Application Laid-Open Publication No. 2001-35994 (Patent Document 4).